This invention relates to a recording data production apparatus and method, a recording medium reproduction apparatus and method and a recording medium, and more particularly to a recording data production apparatus and method, a recording medium reproduction apparatus and method and a recording medium which allow data sectioned in a plurality of sections to be reproduced in a different order.
FIG. 16 illustrates a typical configuration for an encoder, such as a recording data production apparatus, for producing data to be recorded onto a recording medium. A storage apparatus 10 stores video data to be recorded onto a recording medium such as an optical disk 20. The video data is read out from the storage apparatus 10 and inputted to a video encoder 11, where it is encoded in accordance with the MPEG2 video standards. Audio data to be recorded onto a recording medium is stored in another storage apparatus 13. The audio data is read out from the storage apparatus 13 and supplied to an audio encoder 14, where it is encoded in accordance with the MPEG audio standards. A multiplexer 12 multiplexes the video data inputted thereto from the video encoder 11 and the audio data inputted thereto from the audio encoder 14 and outputs the multiplexed data.
A sector unit 16 divides the multiplexed data inputted thereto from the multiplexer 12 in units of data of 2,048 bytes to form sectors, adds sector addresses to the sectors and outputs the sectors to an error correction circuit (ECC) encoder 17. The EEC encoder 17 collects the data supplied thereto in sector units for sixteen sectors to form an ECC block, adds redundancy data (ECC data) for error correction to the ECC block and outputs the ECC block to a modulator 18. The modulator 18 modulates the data inputted thereto from the ECC encoder 17 and outputs them to a cutting machine 19. The cutting machine 19 cuts an optical disk 20 in accordance with the data inputted thereto.
In operation, video data stored in advance in the storage apparatus 10 are inputted to the video encoder 11, where the data is encoded in accordance with the MPEG2 video standards. In particular, the video data undergoes DCT (discrete cosine transform) processing, quantization processing, VLC (variable length coding) processing and other necessary processing and is then outputted to the multiplexer 12. Concurrently, audio data stored in advance in the storage apparatus 13 is inputted to the audio encoder 14, where it is encoded in accordance with the MPEG audio standards. In particular, the audio data undergoes DCT processing, quantization processing, VLC processing and other necessary processing and is then inputted to the multiplexer 12. The multiplexer 12 time division multiplexes the video data inputted thereto from the video encoder 11 and the audio data inputted thereto from the audio encoder 14 in accordance with the MPEG2 system standards to produce data in the form of a multiplexed stream.
The data outputted from the multiplexer 12 are inputted to the sector unit 16, by which they are divided into sectors each including data of 2,048 bytes and a sector address is added to each of the sectors. The resulting sectors are inputted to the ECC encoder 17. The ECC encoder 17 adds redundancy data for error correction to the data inputted thereto and outputs resulting data to the modulator 18. The modulator 18 modulates the data inputted thereto from the ECC encoder 17 and supplies the modulated data to the cutting machine 19.
The cutting machine 19 modulates light to be irradiated upon the optical disk 20 in accordance with the data inputted thereto from the modulator 18 to record the data onto the optical disk 20.
Then, the optical disk 20 is developed, and a stamper is produced using the optical disk 20 as an original disk. A large number of replica disks are then produced from the stamper.
FIG. 17 shows a typical construction of an optical disk apparatus for reproducing signals recorded as data on a replica disk. A pickup 51 irradiates a laser beam upon an optical disk (replica disk) 50 and reproduces data recorded on the optical disk 50 from reflected light of the laser beam. Consequently, a reproduction signal in the form of a radio frequency (RF) signal is outputted from the pickup 51 and inputted to a demodulation circuit 52 where it is demodulated. The demodulation circuit 52 outputs a demodulation output to a sector detection circuit 53 and an ECC circuit 56.
The sector detection circuit 53 detects a sector address from within the demodulation output inputted thereto from the demodulation circuit 52 and outputs the detected sector address to a control circuit 54 which may be a microcomputer or the like. The control circuit 54 receives a state signal designating a stored amount from a ring buffer memory 57. The control circuit 54 suitably controls a tracking servo circuit 55 in response to an output of the sector detection circuit 53 and an output of the ring buffer memory 57 so that the pickup 51 may be fed to a predetermined track position of the optical disk 50. An inputting section 61 is manually operated in order to input a predetermined instruction to the control circuit 54.
The ECC circuit 56 effects error correction processing of the demodulated output signal inputted thereto from the demodulation circuit 52 and outputs resulting data to the ring buffer memory 57. The ring buffer memory 57 temporarily stores the data inputted thereto from the ECC circuit 56 and outputs a state signal designating a stored amount of the data therein to the control circuit 54.
A demultiplexer 58 demultiplexes data read out form the ring buffer memory 57 in accordance with the MPEG system standards and outputs audio data to an audio decoder 59 while it outputs video data to a video decoder 60. The audio decoder 59 decodes (that is, performs inverse VLC processing, dequantization processing, inverse DCT processing, and so forth) the audio data in accordance with the MPEG audio standards and outputs resulting data to a loudspeaker or the like (not shown). Meanwhile, the video decoder 60 decodes (that is, performs inverse VLC processing, dequantization processing, inverse DCT processing and so forth) the video data in accordance with the MPEG2 video standards and outputs resulting data to a monitor apparatus (not shown).
In operation, the pickup 51 irradiates a laser beam upon the optical disk 50 and reproduces data recorded on the optical disk 50 from reflected light of the laser beam. A reproduction signal outputted from the pickup 51 is inputted to the demodulation circuit 52, where it is demodulated. The data demodulated by the demodulation circuit 52 is inputted to the sector detection circuit 53, which detects a sector address. The control circuit 54 discriminates a current position of the pickup 51 from the sector address supplied thereto from the sector detection circuit 53 and controls, when the current position is not a desired position, the tracking servo circuit 55 so that the pickup 51 is fed to a predetermined sector address position. Consequently, the data recorded at the predetermined position of the optical disk 50 is reproduced by the pickup 51.
The data outputted from the demodulation circuit 52 is inputted to the ECC circuit 56, which performs error detection and correction and resulting data from the ECC circuit 56 is stored in ring buffer memory 57. Demultiplexer 58 reads out data from ring buffer memory 57, demultiplexes the same into audio data and video data, and outputs the audio data to the audio decoder 59 and the video data to the video decoder 60. The audio decoder 59 decodes the audio data inputted thereto and outputs resulting data to a speaker (not shown). Concurrently, video decoder 60 decodes the video data inputted thereto and outputs resulting data to a monitor (not shown).
Each of the audio decoder 59 and the video decoder 60 outputs a code request signal to the control circuit 54 when decoding processing therewithin is completed. The control circuit 54 controls the ring buffer memory 57 in response to the code request signals to read out data stored in the ring buffer memory 57 and output the thus read out data to the audio decoder 59 and the video decoder 60 via the demultiplexer 58.
The control circuit 54 monitors a state signal inputted thereto from the ring buffer memory 57 and controls the position of the pickup 51 via the tracking servo circuit 55 so that the ring buffer memory 57 may not overflow or underflow.
The input data rate to the ring buffer memory 57 is set at a value sufficiently higher than the output rate from the ring buffer memory 57. The ring buffer memory 57 has a capacity at least corresponding to a maximum latency time of the optical disk 50 so that data of a variable rate inputted to the ring buffer memory 57 can be outputted continuously at a predetermined output rate. (Assuming the optical disk 50 is a constant linear velocity (CLV) disk, the capacity corresponding to a maximum latency time is the data capacity on the outermost circumference of the disk).
Video data and audio data can be recorded and reproduced digitally onto and from the optical disk 50 in the manner described above.
A drawback of the system described above, however, is that data recorded on the optical disk 50 are successively reproduced in order. To reproduce the data in a different order than the order in which it was recorded on the disk, the inputting section 61 must be manually operated to designate an order of reproduction into control circuit 54, every time a different order is desired.
When video data is recorded, for example, as shown in FIG. 18, in the order of blocks A, B, C and D, it is sometimes desired to reproduce the block D while skipping block C after the block A and the block B are reproduced (reproduction order 1) or to successively reproduce the block C and the block D while skipping the block B after the block A is reproduced (reproduction order 2).
It is assumed that, for example, images of the video data recorded in the block C include some images which are not very preferable to viewers of a predetermined age group. In this case, for viewers of the age group, it is preferable to effect reproduction in the reproduction order 1 so that images of the block C may not be reproduced.
Similarly, when it is desired to prevent viewers of another age group from viewing images of block B, reproduction must be performed in the reproduction order 2, which skips block B. Where the optical disk 50 is a digital video disk (DVD), a parental rate (ages for which viewing is permitted) can be recorded so that predetermined images may not be seen by viewers of a predetermined age group in this manner. In particular, when the digital video disk is to be reproduced, if a viewer manually operates the inputting section 61 to input the age of the viewer, the system can inhibit reproduction of images which are not preferable to the associated age group.
However, with the above-described system, while a parental rate can be recorded which represents, for example, that viewing of block B or C by underage viewers is to be prevented, since the length of block B or C is arbitrary, if reproduction is performed skipping block B or C as shown in FIG. 18, then ring buffer memory 57 will underflow. Consequently, data flow to audio decoder 59 and/or video decoder 60 is temporarily suspended, and a situation may develop in which some of the desirable images are missed.